There are many kinds of polysiloxanes, which are mainly divided into three categories according to the chemical structure and properties of products: ① Silicone oil (modified silicone oil) is a linear polymer with low molecular weight (generally below 10 thousand), and its molecular structure will be grafted and modified in order to achieve certain properties. Colorless or yellowish transparent liquid, hydrophobic and oleophobic, with high boiling point and low freezing point, good heat resistance and chemical stability, used as chemical additives in all walks of life; Among them, the most common ones can be used as defoamer, hydraulic oil, advanced lubricating oil, filler surface treatment agent and demulsifier, emulsion coagulant, waterproof/water reducer for building materials, textiles, paper and other substances, lubricant and release agent in plastic industry, hair humectant for personal care, foam stabilizer in foamed polyurethane, and leveling agent gold type agent in agricultural ink and coating industry. It is also a good electrical insulator. ② Silicone rubber is a kind of linear structure polymer with large molecular weight (100000). Adding fillers and other additives, after vulcanization, the elastomer, namely silicone rubber, can be obtained. Silicone rubber has the characteristics of electrical insulation, chemical stability, physiological inertia and good elasticity in a wide temperature range. It is mainly used to make rubber products used at high or low temperature and artificial organs needed for plastic surgery. ③ Silicone resin is a linear structure polymer containing active groups, which can be further cured. It can be used as advanced heat-resistant electrical insulating paint (silicone paint), heat-resistant plastic (silicone plastic), laminated glass cloth and protective coating.